Titanomagnetites from a Differentiation Sequence, Analcime-Olivine Theralite to Analcime-Tinguaite

J. F. G. Wilkinson
Department of Geology, The University of New England, Armidale, New South Wales

Summary: Six titanomagnetites from a differentiated alkaline intrusion have been studied using mieroscopie, chemical, and X-ray techniques. The titanomag-netites are homogeneous; with differentiation their FeO and TiO2 contents decrease, and Fe2O3 increases. The titanomagnetite course of crystallization extends from close to the ulvöspinel-magnetite join, near to ulvöspinel, towards magnetite. The recalculated normative compositions of three titanomagnetites indicate that they are essentially Fe3O4-(γ-FeTiO3)-(γ-Fe2O3)solid solutions. The changing chemistry of the titanomagnetites is ascribed primarily to variations in the chemistry of the magma during differentiation.

Mineralogical Magazine; 1965 v. 34; no. 268; p. 528-541; DOI: 10.1180/minmag.1965.034.268.46
© 1965, The Mineralogical Society
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